/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @author Stepan M. Mishura
 */

package org.apache.harmony.security.asn1;

import java.util.Arrays;

import org.apache.harmony.security.x501.AttributeType;

/**
 * Represents Information Object Set.
 * 
 * @see http://asn1.elibel.tm.fr/en/standards/index.htm
 */

public class InformationObjectSet {

	private static class Entry {
		public int[] oid;

		public Object object;

		public Entry(int[] oid, Object object) {
			this.oid = oid;
			this.object = object;
		}
	}

	private final int capacity;

	private final Entry[][] pool;

	public InformationObjectSet() {
		this(64, 10);
	}

	public InformationObjectSet(int capacity, int size) {
		this.capacity = capacity;
		pool = new Entry[capacity][size];
	}

	public Object get(int[] oid) {
		final int index = hashIntArray(oid) % capacity;

		// look for OID in the pool
		final Entry[] list = pool[index];
		for (int i = 0; list[i] != null; i++) {
			if (Arrays.equals(oid, list[i].oid)) {
				return list[i].object;
			}
		}
		return null;
	}

	// FIXME change me to Arrays.hashCode(int[])
	private int hashIntArray(int[] array) {
		int intHash = 0;
		for (int i = 0; i < array.length && i < 4; i++) {
			intHash += array[i] << (8 * i); // TODO what about to find better
											// one?
		}
		return intHash & 0x7FFFFFFF; // only positive
	}

	public void put(AttributeType at) {
		put(at.oid.getOid(), at);
	}

	public void put(int[] oid, Object object) {

		final int index = hashIntArray(oid) % capacity;
		// look for OID in the pool
		final Entry[] list = pool[index];
		int i = 0;
		for (; list[i] != null; i++) {

			// check wrong static initialization: no duplicate OIDs
			if (Arrays.equals(oid, list[i].oid)) {
				throw new Error(); // FIXME message
			}
		}

		// check : to avoid NPE
		if (i == (capacity - 1)) {
			throw new Error(); // FIXME message
		}
		list[i] = new Entry(oid, object);
	}
}